In 2013, the pill scare in France has underlined the need for identifying at risk women before the first prescription of combined Oral Contraceptive (COC) to prevent the potentially life-threatening risk of Venous Thromboembolism (VTE). However, no efficient and powerful tool is currently available to achieve this goal. We have developed a clinico-biological prediction score whose performance is encouraging. However, it needs to be improved before it can be used in clinical practice. Capitalizing on unique preliminary genomic data already obtained and 2 case-control studies specifically designed to identify biomarkers for COC-induced VTE (PILGRIM and PILGRIM2), the ROSA-VT project has 3 objectives: (i) Improvement of the PILGRIM score by including new genetic variants obtained by different strategies already implemented by our teams; (ii) Identification of a proteomic signature of the risk of VTE in COC users; (iii); Derivate and validate a new clinic-biological score based on the new biomarkers identified through objectives I to II to predict the risk of VTE on COC in clinical practice. The ROSA-VT intends to solve a public health issue. The information generated will contribute to improve the prediction of VTE occurrence in COC users by identifying and validating new biomarkers (proteomic and genetic). It will also allow the development of a dedicated VTE risk score for women on COCs and has considerable potential for prevention in women before contraception is prescribed. This targeted preventive strategy, based on the choice of the appropriate type of contraception according to the score, will decrease the incidence rate of VTE in women of childbearing age. Early detection of women at risk to prevent the onset of the disease will improve patient care and quality of life, avoiding both overmedicalization and nonessential interventions.